This study aims to obtain the best operating conditions including pyrolysis time and amount of catalyst in oil fuel production from reject plastic as raw material with coal fly ash as catalyst based on its yield and characteristics. Both reject plastic and coal fly ash are waste originating from a paper industry in Medan. This research was carried out in three steps: preparation of reject plastic and coal fly ash, oil fuel production and characterization (composition of coal fly ash and density, viscosity and heating value of oil fuel). The main components in the coal fly ash are SiO2, C and Al2O3 that are 30.36%, 27.11% and 24.04% respectively. The yields of oil fuel are in the range of 14.18% - 26.58%. From 12 samples, 10 samples meet the standard density whereas 8 samples meet the standard viscosity for diesel fuel based on ASTM D-975. The best operating condition is achieved when using 15% catalyst with 2 h pyrolysis time that produce oil fuel with the highest heating value.
This study aims to determine the performance of a continuous and intermittent sun drying of fermented-cocoa bean by using thin-layer drying method. Continuous drying using a solar dryer finned-flat plate collector type which is operated in two modes drying time, daytime and night time. During the day, the cocoa beans are dried in the drying chamber using hot air generated by the solar collectors. In the nighttime, desiccant (CaCl2) was added to the drying chamber that had been isolated. Open sun drying as intermittent drying of cocoa beans is done only on daytime. The drying process is terminated when equilibrium moisture content has been achieved. The results showed that the continuous drying rate higher than the intermittent drying. Dried-cocoa beans produced from continuous drying showed a lower moisture content (7.34% vs 7.50%), a better physical appearance, but the higher the degree of acidity (pH = 5.93 vs. 6.13). Total fat content and free fatty acids slightly lower than the intermittent sun-drying.ABSTRAKPenelitian ini bertujuan untuk mengetahui performa pengeringan kontinyu dan terputus pada biji kakao fermentasi menggunakan metode pengeringan lapis tipis. Pengeringan kontinyu menggunakan alat pengering surya tipe kolektor pelat datar bersirip yang dioperasikan dalam dua mode pengeringan, waktu siang dan waktu malam. Pada siang hari, biji kakao dikeringkan didalam ruang pengering menggunakan udara panas yang dihasilkan oleh kolektor surya. Pada malam hari desikan (CaCl2) dimasukkan kedalam ruang pengering yang telah diisolasi. Penjemuran langsung biji kakao di matahari sebagai pengeringan terputus dilakukan hanya pada sinag hari. Proses pengeringan dihentikan ketika kondisi keseimbangan kadar air dicapai. Hasil penelitian menunjukkan bahwa pengeringan kontinyu menghasilkan laju pengeringan yang lebih tinggi dibandingkan dengan pengeringan terputus. Biji kakao yang dihasilkan dari pengeringan kontinyu juga menunjukkan kadar air yang lebih rendah (7.34% vs 7.50%), penampilan fisik yang lebih baik, tetapi derajat keasaman lebih tinggi (pH=5,93 vs 6,13). Kadar lemak total dan asam lemak bebas sedikit lebih rendah dibanding penjemuran langsung. Kata kunci : biji kakao fermentasi, pengeringan kontinyu, pengeringan terputus, performa.
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